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' (No Mode.)

1.1. ALLEN. Tool Holder-' No.V 238,322. Patented March 1,1881.

N. PETERS, FHOTOL|THOGRAPHER. WASHINGTON. D. G.

Irl-'sufren rames Arum* @Finca JOHN F. ALLEN, OF NEW YORK, N. Y.

TOOL-HOLDER.

-SP:El(`.?I]"IGA'J.ION forming part of Letters Patent No. 238,322, dated March '1, 1881.

Application led April 1, 1880. (No model.)

To all whom it may concern Beit known that I, JOHN F. ALLEN, of New York, in the State of New York, have invented a new and useful Improvement in Tool-Holders, of which the following is a specification.

My invention relates to holders for tool blades or cutters 5 and it consists in the con struction and combination of parts hereinafter set forth.

In the accompanying drawings, Figure I represents a side view of my improved toolholder. Fig. II is an end View. Fig. III isa front view, and Fig. IV is a top view, of the same. FigV is a top view ot' a tool-holder for a single central or square tool.

Similar letters represent similar parts in lall the figures.

A is the tool-holder, in which the shank or stock c is made square or oblong to iit into the tool-post, and is secured in the same in the usual manner. The head b of this tool-holder is made deeper to give sufficientbearing for the tool steel. In this head b of the tool-holder holes n u or m are made to receive the toolsteel or the -tool proper, B. 1f a straight or central tool is required a hole, ma., is made in the center of the tool-holder, as shown in Fig. V, and is placed 'at an angle with the horizontal plane of the tool-holder, at the same time the square hole is so cut as to present the corner angle ot' the tool steel' to the work. For right and left handed tools two holes, grooves, or channels, n fn, are made into and through the forward part or head, b, of the tool-holder, at a proper angle with the horizontal plane of the tool-holder in one direction, as seen in Fig. I, and diagonal to each other and to the front face of the toolho1der in the other direction, as shown in Figs. III and IV. In this case the sides of the holes n ln may be cut parallel to the sides ofthe tool-holder, or only slightly inclined to the same. In large tool-holders the holes n n and m may be made iirone and the same holder.

In the upper part 'of the tool-holder a setscrew, o, is arranged within the plane bounded by the sides of the shank, and in a direction to'act nearly square against the back of the tool B; and in the lower part of the head b of the tool-holder a second set-screw, w, is arranged, likewise within the plane bounded by the sides of the shank a of the tool-holder, and acting, consequently, diagonally upon the back of the toolfB, and likewise diagonal to the set-screw c, by which arrangement a perfectly firm gripe on the tool B is obtained.

The steel tool B requires to be only about one-half of an inch square or round, and is applicable for a-central as well as for a right or left handed tool, and requires only to have the edge or cutting-point ground, without any necessity for forging.

At the back of the tool steel slight recesses may be ground to increase the grip@ of the set-screws and prevent slipping wheu't-aking a heavy cut. These recesses arereadily ground, and will be found necessary for tool steel that is hardened throughout, such as Mushets steel, and as they are at the back of the tool steel no further damage will thereby be done to the tool itself. The upper screw, n, bears against the blade or tool B in a line at right angles therewith, while the lower screw, W, being horizontal, hears against said blade in a line which makes an obtuse angle with said blade. The lines of pressure of these screws (c and 'w would cross one another, if prolonged;

hence their combined action on the blade is a converging pressure, which holds said blade much more tirmly than a single set-screw or two set-screws pressing in parallel lines.

I am aware that it is not new to employ a screw for clamping a tool-blade in a holder; also, that it is not new to make tool--holders with several ways in them, for the purpose of allowing tool-blades to be set at different angles.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

l. In combination with a tool-holder and a tool-blade held therein, a pair of set-screws which bind against said blade in converging lines of pressure, substantially as and for the purpose set forth.

2. In combination with tool-holder A and blade B, a pair of screws, o w, binding against said blade in converging lines of pressure, said blade being provided with recesses to receive the ends ot' said screws, substantially as and for the purpose set forth.

3. In combination with set-screws u fw, one

IOO

above the other, and having` converging lines of pressure, the stock A, having` recesses or grooves extending in differentdirections, said screws working through screw-threaded passagesinto said grooves and clamping the blade B, substantially as shown.

4. The stock A, screw-tapped to receive fastching-screws o and w, recessed to receive the head of the upper screw, o, and provided with two or more grooves or channels, n, which are 1o inclined in different directions, in combination with said screws and with blade B, adapted to be shifted from one to another of said grooves or channels at will.

JOHN F. ALLEN.

Witnesses: A

HENRY E. ROEDER, S. A. EMANUEL. 

